An organic electroluminescent (hereinafter, sometimes referred to as “organic EL”) element is constituted by comprising an anode, a cathode, and an organic light-emitting layer containing a light-emitting organic material. When a voltage is applied to an organic EL element, holes are injected from an anode and electrons are injected from a cathode, and then the injected holes and electrons are recombined in a light-emitting layer, so that the organic EL element emits light.
Organic EL elements have an advantage that their production step is simple and they can easily afford a large area, because organic layers such as light-emitting layers can be formed by an applying method. Specifically, an organic light-emitting layer can be formed by applying an organic solution containing a light-emitting organic material to form a film and then calcining the formed applied film. For example, for conventional organic EL elements, an organic light-emitting layer is formed by performing calcination of an applied film in a nitrogen atmosphere, and after transfer to a vacuum deposition machine, a cathode is formed (see, for example, Patent Document 1).
Patent Document 1: Japanese Patent Laid-Open Publication No. 2005-259720